The present invention relates to a system for displaying plant conditions for providing information to an operator who is carrying out a plant operation by utilizing a computer or computing system, particularly to a plant condition display system for providing plant information suitable for information processing or decision making carried out by a human such as an operator of the plant.
In the operation of a large plant such as a nuclear power plant which involves numerous items of information and which requires safety, the role of an operator or operators is important. Particularly, in view of their serious effect on the plant, problems caused by humans such as errors in control and the methods of their prevention are most important.
An plant operator comprehends the present condition or state of the plant on the basis of information from plant information display instruments on a control board or panel (hereinafter referred to as plant condition comprehension) and accordingly carries out control operation required for the running of the plant. In such operation, an unexpected result may arise in some cases through an erroneous operation due to a simple mistake or insufficient plant condition comprehension of the operator. This latter cognitive insufficiency is caused by the difficulty of the operator to judge only in his mind, the mutual relationships between the items of information obtained from conventional display instruments or the like such as meters and recorders.
In order to prevent such erroneous operations due to the insufficient plant condition comprehension of the operator, there is provided means for displaying, on a CRT (cathode ray tube) screen, the operating conditions of the plant equipment, which has been generally called a P&ID screen for displaying the operating conditions of the plant equipment.
In the information display by such a P&ID screen, it is possible to display individual conditions of each of the items of equipment constituting the plant, but it is insufficient for a total comprehension of the plant condition in all cases. For example, it is insufficient to transfer the information with respect to a secondary influence or effect between sub-systems mutually related in a complicated manner. That is, prime importance is given to the detailed and accurate transmission of individual elements and information for totally grasping surrounding conditions, reasons and objects is insufficient. For the reasons described above, it becomes difficult to clearly comprehend an image of the total condition or state of the plant. Accordingly, the conventional P&ID screen type display merely shows in what condition the plant is, and it is necessary for the operator to think out in his mind highly abstractive conceptional information such as the goal condition of the plant and effects resulting from the present state of the plant.
As described above, it can be said that the conventional system or method of displaying the present state of the plant is insufficient for displaying the items of information suitable for the cognition or perception of operators. Accordingly, plant supervisory control errors may occur due to such insufficient comprehension of the plant condition or incomplete estimation of the plant condition, which will significantly adversely affect the plant operation. Particularly, in a condition where the work load of an operator required for recognizing and diagnosing an abnormal condition becomes high, the operator, with high possibility, searches and recalls an information pattern which is most similar to the subject problem and was encountered in his past experience and adapts the treatment or countermeasure which was utilized in the past experience. As a result, an important information may be overlooked or misunderstood as a similar case which occurred in the past.